Linux tee Guide

Complete beginner-friendly guide to tee on Linux, covering Arch Linux, CachyOS, and other distributions including duplicating output, logging, and output redirection.

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Table of Contents

1. Understanding tee
2. tee Basics
3. Output Duplication
4. Logging
5. Troubleshooting

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Understanding tee

What is tee?

tee duplicates output to files and stdout.

Uses:

• Duplicate output: Send to file and screen
• Logging: Save output while viewing
• Pipeline tool: Split output streams
• Debugging: Save output for analysis

Why it matters:

• Logging: Save output while viewing
• Debugging: Capture output
• Monitoring: Watch and log simultaneously

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tee Basics

Basic Usage

Simple example:

# Save to file and display
ls -l | tee output.txt

# Shows on screen and saves to file

Append Mode

Append to file:

# Append mode
ls -l | tee -a output.txt

# -a = append (doesn't overwrite)

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Output Duplication

Multiple Files

Save to multiple:

# Multiple files
ls -l | tee file1.txt file2.txt

# Saves to both files

With sudo

Save with sudo:

# Save to protected file
ls -l | sudo tee /root/output.txt

# tee needs sudo, not ls

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Logging

Command Logging

Log commands:

# Log command output
command | tee log.txt

# View and save

Script Logging

In scripts:

#!/bin/bash
{
    echo "Starting script"
    # commands here
} | tee script.log

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Troubleshooting

tee Not Found

Check installation:

# Check tee
which tee

# Usually in coreutils
# Install if missing
sudo pacman -S coreutils

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Summary

This guide covered tee usage, output duplication, and logging for Arch Linux, CachyOS, and other distributions.

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Next Steps

• echo Guide - Text output
• Bash Scripting Guide - Scripting
• tee Documentation: man tee

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This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.